Thoughts around Ogive's, seating depths and bullet comparactors

[grendelnubi]

[A5BLASTER]

Well let me try and put my thoughts into words.

So you took a bullet you didn't know where the olive would contact the lands in your rifle. Used a contact measurement for a whole diffrent bullet.

And now feel that useing the proper tool you should have used the first time is simple a wistful repetive task and the whole reloading industry should stop useing a long well established method to something you would rather use.

I think I will just keep chugging along measuring contact to lands in each of my chambers with the hornady tools. And never have too worrie about such a issue as you ran into today.

Slow and safe is in my book a better method too messurments and working up loads then any other way or idea I have heard of.

I understand you fill or belive their should be away too measure something more quickly are set up some kind of system that says ok if you get this contact measurement with this bullet olive you can seat everything else the same.

But I'm afraid it will never work that way.

Every barrel is diffrent and every bullet is diffrent got too do the work or unsafe conditions will happen. As you found out today.

And for what it's worth I know almost nothing about loading compared to most members of this board. So please don't think I'm coming off as a expert or something like that. It's just there are methods and established procedures for safe loading for a reason

[LtDan]

Yes I have done the same thing as I have 5 Grendel Barrels. For each bullet (9 of Them) I measure Base to the lands and then to Base to Ogive. I also measure with a bullet who's base squared off with a lathe to measure the throat depth. Of course every barrel supposedly SAAMI are different dimensions. This I do as I often use a bobsled to load up close to the lands, single loading o me it's all about accuracy.

[sundowner]

Using the tool is the only way to be consistence with your loading and each bullet has it's own Ogive w3hick you use . The only way for what you want to do is to get the bullet manufactures to make all their bullets the same . When I load to COAL I also have problems that why I changed to use Hornady's tools .

[Arkhangel5]

GrendelNubi,

I do something similar with respect to base to ogive measurements.

I have an index card for each rifle I shoot. On the card I put bto measurements of each bullet I intend to shoot in that rifle. In addition to the bto, I also put the overall length of each bullet with respect to where they contact the lands.

This way I can glance at the index card and adjust my seating depth according to what I want to do, whether jumping or jamming. Depending on which rifle I am loading for.

I recently did the same thing you did when switching from 80gr A-max to 80gr ELDm in my match .223. If had used the Amax data, the ELD would have been jammed 20thou into the rifling.

One other thing I think is very important with your measurements, is to always use the same measuring tool on all your chosen bullets.

My 2c

SY

[centerfire]

I have a whole spreadsheet that I document each projectile ogive to base measurement relative to rifle lands. I had an issue recently where I did not measure where the Hornady 129 gr interlock hit the lands and decided to just duplicate another load I have that shoots the 129 gr projectiles well and use the Hornady recommended COAL. The results were excessive pressure signs, deepest ejector and extractor marks on the brass I have ever seen. Ruined the whole day. I later discovered that the projectile was 20 thousand into the lands.. My mistake.....

This caused me to think about a few things regarding how the bullet comparator measures the ogive to base and how it plays in determining proper seating depth that affects jump.
I concluded there is a huge limitation to how bullet comparator works relative to what we are trying to accomplish, and it forces us to go through a series of repetitive steps that we shouldn’t have to go thru for each new projectile we want to shoot.

The root of the issue is where the bullet comparator makes the measurement relative to the projectile ogive. This location varies relative to the ogive profile, it is in fact inconsistent due to ogive profile variations of different style projectiles. This is what contributes to us having to go through repetitive steps to determine proper jump for each new projectile we want to try.
The solution in my humble mind would be to change where the comparator makes the measurement from on the projectile. For consistency sake that could only be one place, the leading edge of the bearing surface. Not on the bearing surface itself because that would not work but within .001 of the leading rim of the bearing surface. This would then remove the inconsistency of using the ogive to base and allow us to use the same bearing surface measurement to base across different projectiles to on the fly get the same jump regardless of the ogive profile.

I am assuming the following;
The bolt face to lands is constant
The bearing surface is the first to make contact with the lands. There are rifling variances but largely true.
The diameter of the comparator hole is constant.
Every projectile has a bearing surface that should be .264 for a 6.5 projectile.
The only inconsistency would be the ogive profile which causes the issue.

Does this make any sense at all?
Sorry up front for the long write up......

Almost every measurement you stated should be consistent is actually a variable. Head space is a range, chamber reamers wear, bullet diameters are sometimes smaller than stated, comparator holes have variation, etc. The only constant is your use of the same tool every time.

[outdoorgeneralist]

The comparator measurements are strictly that, "comparative." The measurements you get are for your own reference only, and to give you a more accurate idea of how consistent your seating depths are. COAL is sometimes not an accurate judge of consistency because of slight variations in the meplat of the bullet.

The comparator inserts themselves, if I understand correctly, aren't machined to the type of tolerances you're asking for in a tool that measures from approximately one-thousandth linearly ahead of the beginning of the bearing surface. This is why a measurement on a any given bullet cannot be passed from handloader to handloader each with separate comparator inserts, even if they are the same brand and part number.

It really doesn't take that long to gather the bullet jump data on each new projectile you load. When seating past published COAL data, it's really the only safe way to do things.

[grendelnubi]

Thanks to everyone for the comments. It all makes a lot of sense, however, I was hoping there was room for improvements on how the comparator works to make it more consistent between projectiles. I'm sure if there is a way, it would have already been done by someone who is a lot smarter than me.

[Mad Charlie]

I use the Forster Micrometer seating die with a lapped seating stem. When I first started loading the 120 Gold Dots I set up to seat at 2.250 COAL, mag length basically. I got some pretty good groups, 6's-8's, more 8's than 6's though. So this last box I loaded I added another step. I decided to check each cartridge's CBTO, and found a pretty fair variance. I decided to qualify the ogives by finding the shortest and using the micrometer seater to go back and make them all the same. My idea was that I would get a more consistent engagement with the lands from shot to shot, assuming they stay where I left them as they cycle through the action. I also weight sorted this box of bullets, which will probably not mean much, as they all were within 1gr of mean or less with most being right on the mean +/- a tenth of a grain.

Haven't had time to get them on the range yet to see if that extra work was worth it. It was already just fine for hunting ammo, but I like to tweak and tune my stuff, gives me the warms and fuzzies. Not to mention confidence. Fewer excuses though...No such thing as ammo that is TOO accurate.

[Drillboss]

Thanks to everyone for the comments. It all makes a lot of sense, however, I was hoping there was room for improvements on how the comparator works to make it more consistent between projectiles. I'm sure if there is a way, it would have already been done by someone who is a lot smarter than me.

This falls into the category of "it is what it is". SAAMI specs allow for bullet diameters to range between 0.2643" and 0.2613". I talked to Hornady once to find out the ID of their .26 caliber comparator and it seems like it was about 0.25" (can't find my notes to be exact). At any rate, I'd be surprised if their tolerances were +/- 0.001" for that item.

Like others have said, we just have to use the tools we have available to check every different bullet we use and hope that tolerances are good enough to run with.

[LtDan]

Here is what I am using and so far it works very well

[Mad Charlie]

This falls into the category of "it is what it is". SAAMI specs allow for bullet diameters to range between 0.2643" and 0.2613". I talked to Hornady once to find out the ID of their .26 caliber comparator and it seems like it was about 0.25" (can't find my notes to be exact). At any rate, I'd be surprised if their tolerances were +/- 0.001" for that item.

Like others have said, we just have to use the tools we have available to check every different bullet we use and hope that tolerances are good enough to run with.

Hornady told me .256